On Friday, as soon as Mu Xueran entered the classroom, he heard everyone discussing the game between Creation and Divine Pavilion yesterday.

"Yuki-dye, your car keys. Ren Mengxin slipped the keychain and shook it in front of Mu Xueran.

Mu Xueran took the key and put it in her backpack.

Ren Mengxin came over again, folded her arms together, lay on the table, and said a little listlessly, "Tomorrow is a holiday, what are your plans?"

"Probably going to the lab. ”

"Or is it a big pick?"

"Hmm. Mu Xueran thought that Su Yifei's wedding was coming, maybe there would be something interesting.

......

Sure enough, on the first day of the Dragon Boat Festival holiday, He Xiaomeng called them to 708 for a meeting.

After reading the literature for more than half a month, everyone already has a rough idea of the experiment.

He Xiaomeng discussed with them and preliminarily determined a set of experimental plans.

After the group meeting, Zhou Ying proposed, "Let's divide the work first." ”

Because she is the only junior among the four and has more laboratory experience than the other three, He Xiaomeng asked her to be the captain, which is a bit more responsible.

Everyone nodded, "Okay." ”

Zhou Ying took out her notebook and said, "Senior Sister Xiaomeng said that let's divide at least six, how about we decide on eight first?" ”

"Yes. ”

Zhou Ying nodded, "Then let's start talking about the experimental part." The first is the pre-experiment, in order to determine the optimal concentration of the bacterial solution for easy observation, it is necessary to carry out concentration gradient dilution of the bacterial solution, and we can choose 10-3~10-7 for anaerobic culture. ”

"If you are anaerobic culture, do you also need to autoclave the instruments used?" asked Qu Xiaolin.

"Yes, so before you do the experiment, you need to sort out the instruments that should be used. Zhou Ying looked at Qu Xiaolin and said, "Xiaolin, it's up to you to sort this out, and then check how to match the RS solid culture medium." ”

"Can't you buy ready-made ones?" said Wu Zixing.

Zhou Ying shrugged, "Probably the ready-made ones are more expensive, and the teacher said that it is better to buy the raw materials yourself." ”

“...... All right. ”

Mu Xueran was listening and taking notes, and suddenly thought of something, and raised her eyes to look at Zhou Ying, "Since you want anaerobic culture, you must have an anaerobic incubator." ”

"In the 709 public lab, but I haven't used it. Zhou Ying looked at the three of them and shook their heads. "Then our only gay man, I'll leave this to you, you go and ask your senior sister, and then teach us. ”

Wu Zixing raised his eyes and said, "No problem." ”

Zhou Ying clicked the notebook with a pen, "Well, after the pre-experiment determines the optimal culture concentration, it is the isolation of the strains, and after obtaining the monoclonal bacteria, the genomic DNA must be extracted first, and I will sort out the reagents, instruments and experimental procedures used." ”

Then Xuezhi is responsible for checking how to detect the purity of DNA, and the principle, system, conditions and steps of PCR amplification. I'm in charge of agarose gel electrophoresis. ”

Zhou Ying closed the notebook and said, "Let's sort out the reagents and instruments used in the part of our respective responsibilities and send them to me, and then I will summarize them. ”

"Good. ”

"If that's fine, let's start tidying up now. ”

Wu Zixing got up and said, "I'll go find Senior Sister Xiaomeng." ”

Out of the laboratory, Wu Zixing knocked on the door of 706 next door, He Xiaomeng was not there, so he took out his mobile phone to call her.

"What's wrong, Zixing?"

"Senior sister, I want to ask you how to use the anaerobic incubator?"

"Anaerobic incubator? I'm not in school now, you go to 709 to take a look, there should be a manual next to the incubator, you study it yourself, and I can go back to the lab in the afternoon." ”

"Okay. ”

Here, Mu Xueran opened the notebook and began to check the DNA purity test.

To use ultra-micro spectrophotometer, DNA should have a significant absorption peak at OD260, and protein should have a significant absorption peak at OD280, and the ratio of OD260/OD280 should be measured to judge the purity of the proposed DNA, and the ratio is about 18, indicating that the purity of the proposed DNA is high; greater than 19, indicating that there is a pollution; Less than 16 indicates protein, phenol and other pollution.

Mu Xueran opened the word on the desktop and recorded all of this, the instruments were listed separately, and suddenly thought that the instruments on the picture looked familiar, and when she turned around, there was one on the table opposite.

At this time, Zhou Ying said, "I can't find the specific steps to mention DNA, and the literature only briefly mentions it, and there is no specific process, but I think I seem to have seen it somewhere." ”

Mu Xueran thought for a while, and said uncertainly, "Is there a kit that specifically mentions bacterial genomic DNA?"

"Yes, yes, yes, I remember, we seem to have it in our lab. Zhou Ying patted her head and said, "You help me find out which cabinet it should be in above." ”

Mu Xueran looked up and swept it, pulled over the stool on the side, and stepped on a closet to open a closet, which contained five or six kits of different sizes, one of which said "Bacterial Genome DNA Extraction Kit", but there was only this one.

"Here it is. ”

Mu Xueran got down from the stool, opened the box, and there was a manual on the top, looked at it, handed it to Zhou Ying, and said, "There are steps on it." ”

"Ah, thank you so much. Zhou Ying said with a smile, so that she could directly scan and extract the text.

Mu Xueran checked the reagents in it again, "There is no proteinase K in this." ”

"Are the other reagents enough?" asked Zhou Ying.

"It should be enough, just a few hundred microliters at a time. Mu Xueran said uncertainly.

"Then let's buy another box, I'll write it down first. ”

After the episode, Mu Xueran continued to sit back in her place and check the relevant literature on PCR amplification.

Although there are relevant introductions in high school biology elective textbooks, the books are only theoretical.

In addition, Mu Xueran only read it roughly once when she reviewed, and only remembered that the DNA parent strand provides a template for replication, the helicase opens the DNA double strand, the 4 deoxynucleoxitic acid is the raw material for the synthesis of the daughter chain, the DNA polymerase catalyzes the synthesis of the DNA daughter chain, ATP provides energy for the replication process, and the primer makes the DNA polymerase connect deoxynucleotides from the 3' end of the primer.

As for the reaction system, the use of the PCR instrument and the parameter setting, it is not in the book.

...

"Beauties, I just read the manual of the anaerobic incubator, it seems to be a little troublesome, I have to exhaust and intake many times, Senior Sister Xiaomeng is not there, I don't dare to get started at will. Wu Zi walked in.

Zhou Ying said, "Then wait for the senior sister to come back, at least a week before you can start the experiment, don't worry." ”

Wu Zixing looked at his phone, "It's half past eleven, are you going to eat? ”

Zhou Ying nodded, "Go." ”

Qu Xiaolin got up and stretched, "Go, go, will Xue Ran go?"

Mu Xueran buttoned up the computer, got up and said, "You guys go, I'll go home and eat." ”

"You don't live on campus?" asked Qu Xiaolin.

"I stayed in the apartment opposite. ”

"Well, let's go down together. ”

。